Absorbent articles may include various skin agents. Skin agents can be used either to treat a negative condition, such as skin trauma, or to provide a beneficial effect, such as a pleasing odor. Absorbent articles, for example diapers and feminine hygiene pads are normally in close and sustained contact with an area of skin. Further, absorbent articles are often used on areas of the skin where there is frequent motion. Due to the friction produced by the frequent motion, the area of skin to which the absorbent article is applied may develop either clinical or subclinical symptoms of irritation. Additionally, these areas of the skin are generally moist, providing an environment that promotes the growth of microorganisms, such as bacteria. The bacteria can irritate an area of skin or cause an infection. A variety of skin agents have been added to absorbent articles to lower friction and soothe skin irritation. Additionally, absorbent articles have included other skin agents, such as vitamins or anti-bacterial treatments to provide beneficial effects to users.
The desirability of adding skin agents to absorbent articles has been recognized, however there remains the challenge of determining the amount of a skin agent that transfers to an area of skin. The determination of the amount of skin agent transferred could be used to determine what amounts provide either a positive or a negative effect to a user.
One method uses tape to determine the amount of a skin agent transferred from an absorbent article to an area of skin. The adhesive layer of the tape is placed on an area of skin, after which an absorbent article is positioned over the tape. During the wear time of the absorbent article, skin agent is transferred to the tape surface facing the absorbent article. Following removal of the absorbent article the tape is peeled off the area of skin, and analyzed to determine the amount of skin agent transferred to the tape surface. There are several problems with this method. For example, the tape generally has a smooth surface compared to the irregular surface of skin. As a result, the smooth surface of the tape has a comparatively smaller surface area than an equally sized area of skin. Thus, the tape would be exposed to less skin agent than an equally sized area of human skin, due to the reduction in surface area. In addition, the smooth surface of the tape may allow the skin agent transferred to the tape to be transferred back to the absorbent article or removed there from, by movement of the absorbent article across the surface of the tape. Further, exudates, such as blood, menstrual fluid, urine, sebum (oils) and sweat that can be present on or in an area of skin may affect skin agent transfer, and are not present on a tape.
As such it would be desirable to provide a method for determining the amount of a skin agent that is transferred from an absorbent article to an area of skin.